In the prior art, an FAT system applied to a storage apparatus serves as a tool for managing storage space and memory data of the storage apparatus. However, when data is accessed via an FAT system, a next available cluster is first searched for with the aid of an FAT index table, which also needs to be updated. Under such a situation, a search time is different according to distribution (or a disk fragmentation) of used and available storage spaces of the storage apparatus. Generally speaking, the more dispersed the storage space is distributed, the longer the search time it takes. Moreover, the FAT index table is searched from a header every time the FAT index table is updated. Therefore, the time-consuming flow cannot meet read/write requirements of an apparatus (e.g., a personal video recorder (PVR)) which needs a fast data read/write speed.
In addition, certain environments supporting the FAT file system provide only one read or write authority to a same file at a time. Therefore, when a write operation is desired on a file which has just been read, the file needs to be first closed and then reopened to perform the write operation, and vice versa. However, the above approach inevitably reduces read/write efficiency of a storage apparatus using the FAT system.